Apparatus for simultaneously inductively heating a plurality of articles



May 31, 1949. A. o. WOOD 2,471,471

APPARATUS FOR SIMULTANEOUSLY INDUCTIVELY HEATING A PLURALITY OF ARTICLESFiled March 9, 1945 2 Sheets-Sheet l INVENTOR May 31, 1949. 2,471,471

A. 0. W00 APPARATUS FOR SIMULTANEOUSLY INDUCTIVELY HEATING A PLURALITYOF ARTICLES 2 Sheets-She'et 2 Filed March 9, 1945 INVENTO Patented May31, 1949 APPARATUS FOR,

SIMULTANEOUSLY IN DUQTEVELY HEATING A PLURALITY F ARTICLES Alden G.Wood, Farina, Ohio, assignor to The Ohio Crankshaft Company, Cleveland,Ohio, a corporation oi? Ohio Application March 9, 1945, Serial No.581,854 7 Claims. (01. 219-13) The present invention relates asindicated to parallel multiple inductors and is concerned primarily withinductors having a plurality of workreceiving openings disposed to heatseveral articles equally and simultaneously. In Patent No. 2,271,916,issued February 3, i942, and owned by the assignee of the presentapplication, an inductor is shown and described which is capable of suchequal and simultaneous heating. When several relatively large articlesare to be heated the inductor shown in the patent becomes long, issomewhat difficult to support and requires considerable space making itnecesary to provide special means for its use. It is usually desirableto keep the work-receiving openings canal in size to simplify themanufacture of the inductor and arrange these openings in a compact formto improve convenience of use. The present invention is concernedchiefly with meeting these re-- quirements as to ease of manufacture,convenience of use, and equality of heating.

Accordingly, the chief object of t.-e present invention has been toprovide a multiple hole inductor having substantially equalwork-receiving openings. Another object has been to provide suchinductor with openings co: pactly and symmetrically arranged. An add nalobject has been to provide an inductor having conductors for supplyingthe inducing current so disposed as not to disturb heating at any of itsseveral heating stations. A further object has been to provide means forsubstantially independently cooling the portion of the inductor at eachheating A further object has been to provide means for moving severalarticles simultaneously into corresponding inductors.

Other objects will become apparent from the following description andfrom the accompanying drawings which illustrate one form of my improvedapparatus.

In the drawings:

Fig. 1 is a plan View showing the general form of inductor and the meansfor moving the Work pieces into the inductor openings;

Fig. 2 is an elevation taken as indicated at ?.2 of Fig. 1 and showingthe inductor only;

Fig. 3 is an elevation partly in section taken as indicated at 33 ofFig. 1;

Fig. 4 and 4A show the construction of the upper ends of the pins forsupporting and locating the work pieces; and,

Figure 5 shows an inductor of modified con struction embodying thepresent invention.

In the form of the apparatus illustrated provision is made for heatingfour articles simultaneously, the articles being supported in inductors15*, I and 33 with properly selected clearances. Current of correctfrequency is supby a suitable source Hi to terminals l5 and it. current,if assumed to enter through terminal iii passes in parallel throughinductor members i7 and it which may be individual members as shown orcombined into one member. current through member ll passescircumierentially around inductor loop l0 and that through member 18passes around loop II. It then passes through members 20 and 2|respectively in parallel and then passes circumferentially aroundinductor loops l2 and I3 returning to the source M through inductormember 24- and ZElLE' QdE. 5. When loops ID and I2 have the samesectional areas and encircle articles identical with the articlesencircled by loops H and it current in all of the four loops is the sameand heating in all loops is equal.

To carry away the inductor power loss and to thus maintain maximumconductivity with a min mum amount of copper and to thus insureoperation, an abundance of cooling water is supplied individually toeach inductor loop to insure inductor temperature. Water i or loops l8and ii is supplied through passages 26 and 2'! re pectively in terminal15 and that for loops H. J. is is supplied by passages 29 and 38 throughto inal it and member 2d. Each loop has its individual Water outlet.Fittings 32 and 33 serve as outlet passages for water from loops l0 andI 1 respectively and fittings 35 and 3'3 serve as corresponding outletpassages for loops [2 and I3.

3 illustrates the apparatus for elevating into the inductor loops, theparts, such as bearing races 35, which are to be heat treated. Thiselevating apparatus is carried on the floor of push ding tank. which inturn is supported by a suitable means. This apparatus comprises avertically moveable platform 40 having four groups of three pins eachsuch as 4|, each group of pins corresponding in location with eachinductor loop. The three pins of each group are disposed triangularly,each pin of each group bein a vertex of a generally equilateraltriangle. The upper end of each pin is machined to provide a supportingledge having an ledge 45 to engage a lower side of a bearing race andhold the race at correct elevation and to provide a vertical face withan edge 46 to engage an inner peripheral surface of the bearing race tocenter the race in the corresponding inductor loop. These pins are ofrelatively small diameter to reduce to a minimum the heat generated inthem when the races are being heated.

Platform 40 which carries pins ll supporting the race to be hardened isattached to plate 50 which is carried by elevator i and spaced therefromby members 52 and 53, through bracket 55. The elevator is supported bypiston rod 56. This piston rod is actuated by a piston in cylinder 58.To insure that the elevator moves in a straight line, guide rods Eli and6! are provided which pass through suitable clearance holes in bracket55 and one of them passes through lower support 62 which is alsoattached to the elevator.

Fluid to operate the piston is supplied to cylinder 58 by means ofsuitable piping. Fluid supplied by piping 63 raises the elevator byforcing the piston upwardly and fluid from piping 64 .forces it downproviding rapid and positive movement of the elevator in bothdirections. A fourway valve 65 controls the supply of fluid and isusually operated by a timer-controlled solenoid 65.

In operation the bearing races or other articles to be heat treated aremanually placed on pins 4| and power is applied for an interval of timeusually regulated by a timer, to heat the race. The timer theninterrupts the power supply and by its supply of current to solenoid 66operates valve 65 to rapidly lower elevator and plunge the races into aquenching medium in tank 35. After a predetermined quenching intervalplatform 4i] is again raised by further timed operation of valve 65 andthe races are removed and replaced by other races to be heat treated.

Numerous modifications may be made in the details of the apparatus such,for instance, as combining conductors H and it into one conductor with asingle water passage therethrough. The inductor loops may be attacheddirectly to the conductors. such as loop Ill being joined to conductorsil and Zil with members Hi and H greatly reduced or eliminated and thewidth of space 12 therebetween may be varied. The in ductor loops may beof any desired form to accommodate the part to be heated, but are alwaysdisposed to bridge the space between members such as l and H or betweenadjacent ends of conductors such as H and 20. The number of inductorloops may be increased or decreased as desired and these may bevariously arranged along the connecting conductors. Thus, in Figure 5,there is shown an inductor having a total of six inductor loops I8arranged in groups of three in series and the groups of three beingconnected in parallel. Further, it is not necessary that the loops bedisposed oppositely as shown, but may be arranged in staggered formationalong the supply conductors.

Other forms may be employed embodying the features of my inventioninstead of the one herein explained, change being made as regards themeans and the steps herein disclosed, provided the elements or stepsstated by any of the following claims or the equivalent of such statedelements or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In apparatus of the class described, a multiple inductor comprising apair of substantially parallel conductors defining a plane, eachconductor comprising an inductor loop in series therewith, axes of theloops being in generally parallel spaced positions and perpendicular tothe plane of the conductors, the loops being on generally opposite sidesof the pair of conductors and being disposed to substantially encirclemetallic articles lying in generally parallel positions, the pair ofconductors having a common return circuit conductor lying generallyparallel to the said pair of conductors but remote from the articles tobe heated, and means for supplying inducing current to the pair ofconductors to flow in parallel therethrough to heat simultaneously twoof the said articles being encircled by the aforesaid loops.

2. In apparatus of the class described for simultaneously and equallyheating a plurality of metallic articles, an inductor comprising twogenerally parallel conductors, each conductor comprising an inductorcoil bridging a cut in said conductor and being adapted to beelectrically coupled to an article to be heated, the parallel conductorshaving a common return circuit conductor lying in generally closeparallel relation with generally straight portions of said parallelconductors and remote from the coils.

3. In apparatus of the class described for heating surface zones of aplurality of articles in a limited space, a pair of generally paralleland closely spaced supply conductors, each supply conductor comprising aplurality of inductor coils adapted to serve as inductors to heat thearticles when the articles are in the coils, the coils being disposedgenerally on opposite sides of the pair of parallel conductors and lyingsubstantially in the plane of said conductors, means for flowing currentin parallel through the supply conductors, the inductor coils of eachconductor being in series, and a return conductor lying in closelyspaced parallel relation with the supply conductors and remote from thecoils to neutralize inductive heating by current in the parallel partsof the supply conductors substantially without affecting heating in thecoils.

4. In apparatus for simultaneously heating a plurality of metallicarticles a circuit comprising three closely spaced generally parallelconductors extending generally away from and being con-v nected to asource of inducing current, two of said conductors comprising a deliverybranch and the other conductor being a return branch of the circuit,each conductor of the delivery branch having a plurality of openings,and current conducte ing coils bridging the openings and extendinggenerally laterally from the conductors, the said coils serving asinductors for heating the aforesaid articles and lying substantially outof magnetic fields of the parallel conductors.

5. In an inductor for simultaneously heating a plurality of metallicarticles, two pairs of inductor coils, each coil being disposedgenerally in a corner of a square, conductors connecting the coils ofeach pair in series, a, supply conductor and a return circuit conductorconnecting the pairs of series coils parallel and to a common source ofinducing current, said return circuit conductor lying in close parallelrelation with the conductors connecting the coils.

6. In an inductor for simultaneously heating a plurality of metallicarticles, a plurality of inductor coils, said coils being arranged in aplurality of groups, conductors connecting the coils of each group in aseries electrical relationship, the groups being arranged in parallelelectrical relationship, a supply conductor and a return-circuitconductor connecting the parallel connections of the groups to a commonsource of inducing current, said return-circuit conductor lying in closeparallel relationship with the con; 7

ductors connecting the coils of each group in semes.

7. In apparatus for simultaneously heating a plurality of metallicarticles, a, circuit comprising at least a pair of closely-spaced,generally-parallel conductors extending generally away from and beingconnected to a source of inducing current, at least one of saidconductors comprising a delivery branch and at least one of the otherconductors comprising a return branch of the circuit, saiddelivery-branch conductor having a plurality of openings andcurrent-conducting coils bridging the openings and extending generallyaway from said conductors, the said coils serving as inductors forheating the aforesaid articles and lying substantially out of magneticfields of the parallel conductors.

ALDEN O. WOOD.

6 REFERENCES CITED The following references are of file of this patent:

UNITED STATES PATENTS record in the OTHER REFERENCES American Machinist,March 16, 1944, vol. 88, No. 6, pages 91-93.

